Simultaneous processing of a plurality of rows of plants, especially trellised rows, for example pruning and harvesting, and apparatus for the process.
While this invention is useful with many types of plants and crops that are grown in rows, its presently most important application is for the processing of grape vines. The most modern system for establishing and maintaining vineyards is to provide trellises for the vines. The trellis itself includes a series of upright metal posts set in a row. Trellis wires are stretched between and attached to these posts. Usually four or more of these trellis wires are disposed about a foot above or below from one another, extending parallel to the ground, and attached to the posts by fasteners.
When the vine is first planted, some of its branches are attached to the lowermost wire, and the owner awaits the passage of time. During this time, the lower branches will grow and be trained to establish the cordon, which extends laterally in both directions from the root. Shoots from the cordon extend in many directions including upwardly from it. Only some of them will be selected to form part of the ultimate vine.
Seasonally, workers are brought into the vineyard to train the vines to grow upwardly in a proper pattern. Suitable shoots are selected and trained along the next wire above in order ultimately to provide a trellised vine which covers much of the face of the trellis. However, it is not that simple.
Each year the new growth is much in excess of that which is needed for the next wire, as to the number of shoots, their individual length, and their direction. The conventional way to attend to this is to send a large number of workers into the vineyard to prune the vines, to select the suitable shoots for further growth, to prune off the others, and to train the selected shoots along the next wire. The same thing is repeated again next season.
This technique is surprisingly expensive. The worker must cut (prune) every shoot to some length. Each cut takes time and human effort. In older vineyard systems which do not train their vines in the more modern technique, this is an accepted expense. However, labor has become much more expensive than it was before, and intensive labor expense is no longer tolerable, except for vineyards that produce extraordinary grapes.
Along with the ever-increasing producing acreage of vineyards, grape prices have fallen steeply, sometimes from as high as $2,000.00 per ton to as low as $400.00 per ton for grapes from the same vineyard. It is obvious that labor costs must be reduced, because they have become the major operating expense in vineyard operation. For vineyards of many acres, any labor saving quickly becomes very important.
Apparatus is known for mechanically pruning trellised plants and for harvesting the crop. Such equipment generally is bulky and heavy and is mounted on tractors which must be narrow enough to pass between rows. Rows are usually spaced between about 4 to about 6 feet on centers, so the tractor itself must be rather narrow. The tool is carried by an arm pivotally mounted to the tractor so the tool can be positioned appropriately. This becomes part of a top heavy structure because it must often overhang an adjacent row.
It is informative to note that both sides of a single row are usually engaged by the tool. The tool and its supporting arm exert both a sidewise-tilting and forward-leaning force on a narrow tractor. As a consequence, the tool and tractor can be dangerous to its driver. For example while turning around at the end of a row, the tool adds a tilting centrifugal torque on the tractor. Especially when there is a slope at the end of the row, there is a considerable risk of overturning a narrow gauge vehicle while turning it.
One way to resist the tip-over risk is to provide a wider wheel base (tread, gauge), but the narrow width of the path between adjacent rows precludes this if the driver is to remain seated at a lower elevation. It is, of course, possible to raise the operator above the rows and have the tractor straddle the row. However the apparatus then becomes even more top-heavy, and raises the operator above the trellises where his ability to observe and respond to trellis conditions is compromised.
One can reasonably believe that a doubling of the number of working tools would provide some balancexe2x80x94a tool on each side of the tractor instead of only one on one side. The problem then becomes one of balance and control over two heavy tools and arms mounted to a tractor with a narrow wheel base. These are very considerable problems, and have been considered to be so serious that development of multiple row processing has essentially stopped.
For these and for reasons further to be discussed, apparatus to process two rows simultaneously has not been suitably developed despite its potential advantages. The advantages of having a tool operator process two rows simultaneously rather than one are not fully appreciated. Among the advantages is that only one pass is required for processing two rows instead of processing only one for each of the two rows. The simplistic notion is that production should double, because the operator does two identical things at once instead of only one. Surprisingly, the advantage is closer to three to one. The additional improvement in efficiency is related to human factors, as well as to mechanical ones, and is sufficient to encourage the investment in costlier machinery to process two rows at the same time.
While the time to travel the length of a row is the same when two rows are treated instead of one, there is only one turnaround for every two rows. While the time saving is less than half, it is still significant.
Then there are human factors. Suppose that two single row machines are operating in a vineyard. One breaks down. What does the other operator do? He turns off his own machine, stops, and goes over to help his friend get the other machine started again. Two machines are down, not just one.
Or at coffee break. A man alone in a vineyard will stop for a brief time for coffee when he has no one to talk with. If there are two men, they visit. Time is lost. There are other factors, but these illustrate the advantages of expanding the capacity of a given machine while reducing the number of workers in the vineyard.
It is an object of this invention to provide apparatus simultaneously to process both sides of two adjacent trellised rows, utilizing a tractor whose operator sits on a tractor chassis, at a conventional height between the rows. The steerable front part of the chassis has a width no larger than the row spacing. The rear end of the tractor has a rear wheel base width (gauge) that is much wider than the path between the rows. In fact, the rear wheels run on the opposite sides of the adjacent rows. Such structure does not impede the operator""s view and enables the use of the tractor""s conventional power and drive control systems to be used.
All of the advantages of the conventional tractor remain available in a structure less likely to tip over, and which can process multiple rows at the same time.
Apparatus simultaneously to process a plurality of trellised crop rows according to this invention includes a tractor chassis that includes a power source such an internal combustion engine, a power take-off, a pair of steerable front wheels with a first lateral gauge, means to mount a driver, controls for the power source, and steering controls for the steerable wheels. The tractor has a width and the gauge of said front wheels is small enough to move along a central path between a pair of adjacent rows to be processed. These rows bound the central path on each side.
A bridge is mounted to the rear of the chassis. It extends laterally from and above the chassis. Two struts depend from the bridge. Each strut mounts a rear wheel. The rear wheels are laterally spaced by a larger, second gauge. This second gauge is sufficiently wider than said first gauge so that said rear wheels can move in parallel adjacent paths on the opposite side of the rows which are adjacent to said central path.
A drive train interconnects the power take-off to the rear wheels. The two front and two rear wheels support the tractor. The front wheels steer it and support the front end of the tractor. The rear wheels complete the support of the apparatus and drive the apparatus.
According to a preferred but optional feature of the invention, the bridge includes means to adjust the second gauge, that is, the spacing between the rear wheels. This enables the apparatus to be utilized for processing rows of different spacings.
According to yet another preferred but optional feature of the invention, working tools such as pruners are mounted to the bridge by manipulators which can control the position of the working tools relative to the chassis and its drives, all under control of the driver.
The above and other features of this invention will be fully understood from the following detailed description and the accompanying drawings, in which: